:root {
    --background-color: #2c3e50;
    --border-color: #7591AD;
    --text-color: #34495e;
    --color1: #EC3E27;
    --color2: #fd79a8;
    --color3: #0984e3;
    --color4: #00b894;
    --color5: #fdcb6e;
    --color6: #e056fd;
    --color7: #F97F51;
    --color8: #BDC581;
}

* {
    margin: 0;
    padding: 0;
}

html {
    font-size: 14px;
}

body {
    width: 100vw;
    height: 100vh;
    background-color: var(--background-color);
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Montserrat', sans-serif, Arial, 'Microsoft Yahei';
}

.channel {
    position: absolute;
    width: 80%;
    text-align: center;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -200px);
    font-size: 30px;
    font-weight: bold;
    color: #fff;
}

.loader {
    position: relative;
    width: 80px;
    height: 80px;
    /* background-color: lawngreen; */
    border-radius: 50%;
    border: 3px solid var(--color4);
    transition: 0.5s;
}

.loader.loadding {
    animation: animate_rotate 1s linear infinite both;
    border-color: #34495c;
    border-left-color: var(--color4);
}


/* 变色+旋转 */

@keyframes animate_rotate {
    0% {
        transform: rotate(0deg);
        border-left-color: var(--color1);
    }
    25% {
        border-left-color: var(--color2);
    }
    50% {
        border-left-color: var(--color3);
    }
    75% {
        border-left-color: var(--color4);
    }
    100% {
        transform: rotate(360deg);
        border-left-color: var(--color1);
    }
}


/* 开始做对号 */

.loader::before {
    position: absolute;
    content: '';
    top: 50%;
    left: 18px;
    /* left: 50%; */
    border: 3px solid var(--color4);
    border-left-width: 0;
    border-bottom-width: 0;
    /* background-color: #7591AD; */
    /* 关键点，这个地方琢磨了好久都没搞明白。 */
    transform: scaleX(-1) rotate(135deg);
    transform-origin: left top;
    display: none;
}

.loader.check::before {
    display: block;
    animation: animate_check 1s linear 1 both;
}

@keyframes animate_check {
    0% {
        width: 0px;
        height: 0px;
    }
    33% {
        width: 20px;
        height: 0px;
    }
    100% {
        width: 20px;
        height: 40px;
    }
}